ID(1)			     BSD Reference Manual			 ID(1)

NAME
     id - return user identity

SYNOPSIS
     id [user]
     id -G [-n] [user]
     id -g [-nr] [user]
     id -p
     id -u [-nr] [user]

DESCRIPTION
     The id utility displays the user and group names and numeric IDs, of the
     calling process, to the standard output.  If the real and effective IDs
     are different, both are displayed, otherwise only the real ID is dis-
     played.

     If a user (login name or user ID) is specified, the user and group IDs of
     that user are displayed.  In this case, the real and effective IDs are
     assumed to be the same.

     The options are as follows:

     -G	     Display the different group IDs (effective, real and supplemen-
	     tary) as white-space separated numbers, in no particular order.

     -g	     Display the effective group ID as a number.

     -n	     Display the name of the user or group ID for the -G, -g and -u
	     options instead of the number.  If any of the ID numbers cannot
	     be mapped into names, the number will be displayed as usual.

     -p	     Make the output human-readable.  If the user name returned by
	     getlogin(2) is different from the login name referenced by the
	     user ID, the name returned by getlogin(2) is displayed, preceded
	     by the keyword ``login''.	The user ID as a name is displayed,
	     preceded by the keyword ``uid''.  If the effective user ID is
	     different from the real user ID, the real user ID is displayed as
	     a name, preceded by the keyword ``euid''.	If the effective group
	     ID is different from the real group ID, the real group ID is dis-
	     played as a name, preceded by the keyword ``rgid''.  The list of
	     groups to which the user belongs is then displayed as names, pre-
	     ceded by the keyword ``groups''.  Each display is on a separate
	     line.

     -r	     Display the real ID for the -g and -u options instead of the ef-
	     fective ID.

     -u	     Display the effective user ID as a number.

     The id utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     who(1)

STANDARDS
     The id function is expected to conform to IEEE Std1003.2 (``POSIX'').

HISTORY
     The historic groups(1) command is equivalent to ``id -Gn [user]''.

     The historic whoami(1) command is equivalent to ``id -un''.

     The id command first appeared in 4.4BSD.

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